Circuits to control and drive brushless DC (BLDC) electric motors are known. In some arrangements, the circuits provide a phase advance of drive signals that drive the electric motor, the phase advance related to rotational speed of the electric motor. However, such circuits are only able to provide one relationship between phase advances and rotational speeds.
Some known electric motor drive circuits are described in U.S. Pat. No. 7,590,334, issued Sep. 15, 2009, and U.S. Pat. No. 7,747,146, issued Jun. 29, 2010, both of which are assigned to the assignee of the present invention.
A BLDC electric motor can exhibit different efficiency behaviors versus speed when used in different applications. For example, the same BLDC electric motor can be used with different fan blade arrangements in different applications. Different types of BLDC electric motors can also exhibit different efficiency behaviors versus speed.
In view of the above, it would be desirable to provide an electric motor control circuit and associated method that can generate electric motor drive signals having phase advances determined in accordance with a user selectable relationship between rotational speeds and the phase advances, selected from among a plurality of different relationships.